warehouse roof framing in australia

huangyhg

warehouse roof framing in australia
i am a structural engineer in the u.s. working on a warehouse project in a town just outside of melbourne, australia. originally i was going to spec open web steel joists and joist girders for the roof framing but i was just informed by someone on this forum that open web steel joists are not readily available in australia.
my question now is, what is the most common system used for a warehouse roof in australia? is it custom-built steel trusses or wide flange beams? this building i am working on has 14.4m x 14.4 m bays.
the structural narratives are due in two week. any information you can provide will be greatly appreciated.
thank you.  
typical warehouses use ub and uc (w shape) portal frames with haunches and light gauge z purlins on the roof.
walls are precast panels or clad z purlins.
trusses are not often used and are not easily available prefabricated.
csd72 is correct.  however, i saw on tv a report on the opening of the first costco store in australia, and the roof appears to be framed with open web steel joists.  i don't know where they came from.  someone else on the site may know.  the other difference is that we don't use roof deck for diaphragm action, rather we use horizontal bracing to form trusses horizontally.  generally, we use steel roofing which is the membrane, not a structural element as such.
there are a few fairly large design and supply firms which are into open web type portals.  one is in shepparton can't re  
thank you for the quick response. i found two different z-purlins online. they are stramit and lysaght. are both of these easy to find?
civeng80, if you could please get me a contact that would be wonderful.
it seems to me that employing a consultant with knowledge and experience of australian codes and practice would be a good idea.
  
doug jenkins
interactive design services
yes, stramit and lysaght are probably the two largest purlin manufacturers.
ids
yes, that would seem sensible.
the issue of certifying, by an registered building practitioner, that the building design complies with the bca and australian standard's hasn't yet been raised (on this thread).
we are only retained to perform a study on what type of structural system is most suitable for the function of the building. the actual design will be done by a local engineer.
typical portal framed warehouse details can be found here;
here's the link